The defense representing accused killer Cody Posey entered evidence on Wednesday that a computer found in the Posey residence had been used to access thousands of Web pages of pornography.

Attorney Gary Mitchell has called the aspect one of the "critical portions" of his case, because the sites include father-daughter and mother-son incest.

Posey, 16, has admitted to the July 5, 2004 shooting of his father, Delbert Paul Posey; his stepmother, Tryone Posey; and his stepsister, Marilea Schmid, 13. Posey was 14 at the time. The crimes occurred on Sam Donaldson's Chavez Canyon Ranch in Lincoln County, where Delbert was ranch manager.

Mitchell says the boy's lifetime of abuse pushed him to mentally snap and kill in self defense.

Senior Trial Prosecutor Sandra Grisham has alleged Posey was unhappy because he was forced to work on the ranch. She has said his acts were cold-blooded and premeditated.

Before defense witnesses testified on Wednesday, prosecutors asked Judge James Waylon Counts to suppress the Internet pornography because chain of custody had broken during the post-murder investigation.

During a hearing outside the jury's presence, forensic computer analyst Jack Henderson, an investigator for the district attorney, testified he did not receive the computer until July 14, nine days after the shootings. In addition, Posey was not arrested until mid-afternoon on July 7. Henderson said the computer was accessed on July 7 and 8 -- there was no way to tell by whom -- but that it was "possible" data could have been "altered."

Henderson said whoever did access the Web viewed incest pornography, but he felt the data was corrupted because of the unusual times the computer logged such access.

"In my experience ... (pornography surfing) occurs in the middle of the night," Henderson said. "I've never seen anybody get up at 7 o'clock in the morning and search for porn, and do it again at lunch time and again at 3 or 4 o'clock in the afternoon."

Adding to his suspicion of corrupted files, he cited the pornography goes "back to 1999" before Donaldson hired the Poseys.

Senior Trial Prosecutor Janice Schryer said Donaldson actually owned the computer. Numerous people also had keys to the Poseys' house when the family lived there.

Ruidoso computer business owner Joe Burchett, however, testified he found data in the cache files was dependable.

"The jury will be given an opportunity to determine whether the testimony of Mr. Burchett or the testimony of Mr. Henderson is more reliable," Counts said when he denied the state's suppression motion. "As far as chain of custody ... the court would not suppress the evidence for some gaffe in chain of custody."

During testimony before the jury, Burchett described how he used sexually related words he pulled from the computer's history file to search for the remnants of Web pornography on the hard drive.

"We were looking for things related to incest and along those lines, and other types of pornographic searches," Burchett said.

He uncovered a plethora of pornographic pages he said were purposefully sought, which contained both text and photographs.

One defense exhibit alone was a compilation of 4,000 Web pages accessed via the computer, of which Mitchell said 80 percent were pornographic.

Burchett said the sites were all accessed after 2001 until the deaths in July 2004. Many were incest-related, including father-daughter sites found when the phrase "free incest stories" was typed in; others had names such as "My Sexy Wife Photo Album."

"They're (the surfers) actually looking for images," Burchett said, pointing out that to access the sites the Google "safe search" feature which prevents "accidental viewing" was deliberately disabled.

Mitchell told the Daily News if the entire body of pornographic sites were viewed it would take "six to seven days."

Burchett testified he visited some of the sites and printed off images from the words where "incest" and "daughter" had word hits.

Additionally, he said incest sites were searched for when Hondo school records show Cody and Marilea were in school. Other non-pornography sites such as real estate pages were searched for in the same time frame, in Burchett's opinion showing an adult was using the computer.

Schryer, however, pointed out that "quite a lot of entries" into "sex sites" were on Fridays as well as weekends. Hondo school had a four-day week.

"Let's get to the bottom line on this," Schryer said. "Can you tell the members of this jury who accessed this computer?"

"I cannot say who accessed it at all," Schryer said.

The defense plans to wrap its case today with testimony from two psychologists who examined Posey.

"I expect a lively and entertaining cross examination," District Attorney Scot Key said.

The prosecution will then begin its rebuttal.

"The state will be calling a large number of rebuttal witnesses that will obviously rebut some of the tales of the defense," Key said.